I have a Dell Dimension 3000 computer. Currently I am running off windows XP OS, i have 2 GB RAM (bought from dell), an intel pentium 4 processor 3 ghz, 2.99ghz, Im not sure what my power supply is, im have a graphics controller integrated into the motherboard. I have a mechanical hard drive.
Now I'm fairly new at this but am familiar with the hardware and working of the computer. I just wanna know if i could change the motherboard to one with PCIe slots to handle a video card capable of playing Shogun 2 or other total war games. All my other parts are up to the standards but it seems this is the only problem. What type of motherboard could i use to integrate these other parts. Would it be possible? What would it affect? Would i need to change any software(I shouldnt)? Any help would be great.

Service Tag? No Idea, not sure i should?
Is 3 ghz processing power really that bad? It says on the shogun site that it is above the 2.8 that is needed the recommended system requirnments.
I am certain that it would be easier to build a new one, but i am really short for cash and would much prefer to just change my mobo.
ANy other options?

Service tag is fine, it just enables me to confirm with Dell your exact system specification, before making any further suggestions. It offers no personal information, its purely for hardware identification. Its on a sticker on the side, or top, or rear of the desktop tower.

While the CPU might be enough for now, if you purchase a new motherboard for such old hardware, you will be spending money for the sake of it.

I would strongly recommend you purchase a new CPU cooler as welll, if you go down that route.

I was hoping it would also detail your PSU wattage as well, as this will be a deciding factor when looking to upgrade your GPU as well.

The reason I mention this, is by the time you have purchased a legacy motherboard, a new cooler fan (more on this below) and a new GPU and PSU, you might as well purchase a new budget computer, which would be considerably faster than this in any case.

The reason I mentioned about the CPU cooler is because Dell have a nasty habit of using a proprietary system whereby the case forms part of the backplate for the CPU cooler mounting, and the cooler is simply screwed into the baseplate sandwiching the motherboard and CPU between the two. Its very effective for high volume production environments, but its not how it should be done when using retail parts yourself. Spacers are also glued to the motherboard on the front and back to prevent shorting.

Because of this, a new motherboard will likely short out on the raised backplate portion of the case. It will be impossible without drastic modification to use an aftermarket cooler (or even a genuine new one), and it restricts you to Dell components, just the way they like it.

Before you go ahead ordering though, you need to check your total wattage on your PSU (on the label in case), and confirm how the CPU cooler is mounted. Is it mounted with plastic pins, or is it screwed through the motherboard and held in place by the case behind it.

Thanks very muhc for your help. I think your right that it will just be easier to build a new one. Get new tech that would help me in the long run.
It's a family computer right now anyway so i wouldnt want to go messing around with all this only to mess it up.
How much do you think it will cost me to build a decent gaming computer?